Engine noise diagnose assistance - Possible vario cam actuator/pad/chain issue?

[Homeoboxter]

Originally Posted by blue62

If you are attempting to isolate a sound.

I forget what RPM that is supposed to happen but somewhere around 1500 RPM is when they kick in. Then back out at around 5500 RPM.

For the actuator kicking in at I remember 1500 rpm too, but actually on the first video the changeover is clearly at 2500. The description (see the copies of the book) of the variocam in this thread clearly states 1500rpm though:

https://rennlist.com/forums/996-forum/557016-how-variocam-and-variocamplus-works-a-primer.html

Perhaps that section is referring to the 968 hence the confusion?

[blue62]

Originally Posted by Homeoboxter

For the actuator kicking in at I remember 1500 rpm too, but actually on the first video the changeover is clearly at 2500. The description (see the copies of the book) of the variocam in this thread clearly states 1500rpm though:

https://rennlist.com/forums/996-forum/557016-how-variocam-and-variocamplus-works-a-primer.html

Perhaps that section is referring to the 968 hence the confusion?

Another thing that people fail to consider when using common OBDII readers is the refresh or sample rate of the reader. Durametric, Foxwell, (I have both) whatever. I don't think the sample rate is all that fast.
For example when looking at O2 sensor signals on the Durametric the sample rate (across the bottom of the graph) is in frames over time. Frames per minute IIRC.
A Pico or a good Snapon scanner like a Versus the sample rate is in milliseconds.

So I think the slower sample rate of the common OBDII reader has an affect on the info they display.
Also the more sampling you are trying to do the slower the sample rate becomes.
Your going to get a faster sample rate looking at one 02 sensor signal then you are when looking at all four.
If your looking at cam angle on both banks, Cam deviation, RPM,
Your going to get a much slower sampling or refresh rate then you would get when just looking at RPM alone.

[Homeoboxter]

Originally Posted by blue62

Another thing that people fail to consider when using common OBDII readers is the refresh or sample rate of the reader. Durametric, Foxwell, (I have both) whatever. I don't think the sample rate is all that fast.
For example when looking at O2 sensor signals on the Durametric the sample rate (across the bottom of the graph) is in frames over time. Frames per minute IIRC.
A Pico or a good Snapon scanner like a Versus the sample rate is in milliseconds.

So I think the slower sample rate of the common OBDII reader has an affect on the info they display.
Also the more sampling you are trying to do the slower the sample rate becomes.
Your going to get a faster sample rate looking at one 02 sensor signal then you are when looking at all four.
If your looking at cam angle on both banks, Cam deviation, RPM,
Your going to get a much slower sampling or refresh rate then you would get when just looking at RPM alone.

I don`t know, he was revving up the engine quite slowly, definitely in the second range...